This invention relates generally to chair seats, and in particular to chair seats that are rotatable between a forward position in which a user can sit on the chair and an upright position in which the chair seat is positioned out of the way of a user walking by the chair.
In general, chairs include the following four structures: (1) a seat upon which the user sits, (2) a chair back against which the user leans his or her back, (3) arm rests for supporting the user""s arms, and (4) a support structure for supporting the three previously mentioned structures on the ground. In one particular type of chair, generally referred to as a theater-style chair, the seat is rotatable between a forward position and an upright position. In the forward position, the seat is generally horizontal and allows a person to sit on the seat. In the upright position, the seat is nearly vertical, which allows the space which the chair occupies to be decreased and thereby provide more room for the person to walk by the seat. Stadium style chairs are generally found in sports arenas, stadiums, theaters, and similar types of venues. The seats are generally arranged in continuous rows in which a person has to walk between the rows in order to arrive at their chosen chairs. The chair seats are constructed such that they remain in an upright position until a person sits on them. This allows sufficient room for people to walk between the rows in order to arrive at their seats. This generally allows the rows of seats to be positioned closer together than they otherwise would be able to while still comfortably accommodating the chair users.
In order to provide a chair seat that returns to the upright position after a person has exited the chair, it has been necessary in the past to provide some sort of biasing mechanism to return the chair to this upright position. These biasing mechanisms have often involved springs which undergo torsion when a person sits on the chair seat. When the person exits the chair seat, the torsional force of the spring returns the chair to an upright position. Often times this spring would act against metallic components of the chair and thereby cause undesirable squeaking when the chair seat rotated. Furthermore, the upright position at which the seat came to rest was often determined by the precise angle at which the spring was no longer undergoing any torsional forces. This made it difficult to ensure that the upright position of a succession of chairs aligned in a row was the same. Without such uniformity, the aesthetic appearance of the chairs is diminished.
Past chair seats have also suffered from other disadvantages. As one example, prior chair seats have often required the use of welding and other mechanical fasteners such as screws. The use of both welding and separate mechanical fasteners increases the time and labor necessary to manufacture a seat. Providing additional fasteners also increases the material costs for the chair seat. Another disadvantage of prior chair seats is their predominant use of metallic parts. For those metallic parts which are visible to a user it is often necessary to paint the exterior surfaces of the metal in order to provide an aesthetically satisfactory appearance. This painting step, of course, increases the overall cost for manufacturing the chair. Additionally, when metallic parts are used, they often come in contact with each other. This can lead to undesirable squeaking when the chair seat is rotated or otherwise moved due to the motion of the seat occupant. These and other disadvantages have led to the desire for an improved chair seat that substantially overcomes these problems.
Accordingly, the present invention provides a chair seat whose manufacture requires no welding and no separate fasteners for securing the component parts together. The chair seat is also primarily made out of plastic, which eliminates the possibility of metalxe2x80x94metal squeaking, along with the necessity of painting any exterior surfaces. The chair seat of the present invention also overcomes prior difficulties associated with the spring mechanism and the uniform alignment of the chair seat in its upright position.
A chair seat according to one embodiment of the present invention comprises a bucket and at least one bearing about which the bucket can rotate between a rest position and a forward position. The bearing includes at least one flexible tab that is flexible between a locking and an unlocking position. The chair seat further includes a spring assembly positioned in the bucket which biases the bucket toward the rest position. A bearing block is attached to the bucket and includes an aperture through which the bearing and the flexible tab is inserted. The flexible tab moves to an unlocking position while being inserted through the aperture and returns to the locking position after it has been inserted completely through the aperture. The flexible tab thereby secures the bearing block to the bearing.
A chair seat according to another embodiment of the present invention includes a right and a left bracket which are adapted to be attached to at least one base. A right bearing is attached to the right bracket and a left bearing is attached to the left bracket. The right and left bearings are both made out of plastic. A plastic seat bucket is also provided which includes a right and left aperture for receiving the right and left bearings respectively. The plastic seat bucket is rotatable about the right and left bearings from an upright position to a forward position. The seat bucket further includes right and left seat stops which are integrally molded into the seat bucket. The right and left brackets each include bracket stops which are integrally molded onto the right and left brackets. The bracket stops contact the seat stops and stop the seat bucket when the seat bucket is rotated to a forward position. The chair seat further includes a spring mechanism which resists rotation of the seat bucket to the forward position such that the seat bucket will rotate out of the forward position when a user exits the chair.
According to another embodiment of the present invention, a chair seat includes a bucket and a substrate positioned on top of the bucket. One of the bucket and the substrate contains at least one flexible tab and the other of the bucket and the substrate contains a recess dimensioned to receive the flexible tab. The flexible tab and recess secure the bucket and substrate together without the use of welding or separate fasteners. The chair seat further includes a spring mechanism that biases the bucket and substrate toward an upright position. The spring mechanism is attached to the bucket without the use of welding or any separate fasteners.
According to yet another aspect of the present invention, a spring assembly for a chair seat that is rotatable between a seated position and an upright position is provided. The spring assembly includes a static cam which is attached to the chair seat and maintains the same position with respect to the chair seat when the chair seat is rotated from the upright position to the seated position. The spring assembly further includes a dynamic cam which is positioned adjacent the static cam. The dynamic cam rotates and moves linearly with respect to the chair seat when the chair seat is rotated from the upright position to the seated position. A spring is positioned adjacent the dynamic cam and is compressed by the dynamic cam when the chair seat is rotated from the upright position to the seated position. The spring also undergoes torsion when the chair seat is rotated from the upright position to the seated position. Both the compression and torsion forces experienced by the spring cause the spring to resist rotation of the chair seat to the seated position.
According to yet another aspect of the invention, a method is provided for controlling the movement of a chair seat that is rotatable from a rest position to a forward position. The method comprises providing a spring, a cam member, and a stop on the cam member. The stop on the cam member corresponds to the rest position of the chair seat. The spring is positioned in the chair seat such that the spring undergoes substantially no torsion when the chair seat is in the rest position. The spring is compressed in the chair seat against the cam member when the spring is in the stop position such that the spring exerts a camming force on the chair seat to retain the chair seat in the rest position.